Moderate exercise helps to control asthma in physically inactive adults by reducing the airway eosinophilic inflammation, suggests a recent study published in the Annals of the American Thoracic Society.¹

Does the intensity of exercise impact airway and systemic inflammation in asthmatic sedentary adults? Researchers from Australia set out to examine this question in a randomized controlled trial involving adult patients with asthma and who were physically inactive. All the selected 56 participants, mean age 33.4 years, were randomized into three groups based on the intensity of exercise: 45 minutes of moderate exercise (n = 19) or 30 minutes of vigorous exercise (n = 19), while 18 subjects in the group with no intervention acted as controls. Seventy-five percent of the study subjects were female. Blood and sputum samples were obtained at study entry and 4 hours following the exercise routine.

Compared to the control group, a marked decrease in sputum eosinophil count (–173 x 10⁴/mL) and sputum percent eosinophils (–2.2%) was noted in the moderate exercise group 4 hours post-exercise. However, no such change was noted among the participants in the vigorous exercise group.

This decline in inflammation was particularly evident among those with eosinophilic asthma, who exhibited greater reduction in sputum eosinophils along with higher increase in plasma interleukin-1 (IL-1) receptor antagonist vis a vis patients who had non-eosinophilic asthma.

A rise in serum IL-5 and IL-1β levels was seen among study subjects with eosinophilic asthma after vigorous exercise indicative of a systemic pro-inflammatory response. However, the authors note that this did not modify the airway inflammation.

Asthma is a chronic inflammatory disease of the airways and characterized by airway hyperresponsiveness and obstruction. Based on the predominant cellular infiltrate in the sputum, asthma can be eosinophilic or non-eosinophilic. Persons with eosinophilic asthma are prone to exacerbations.

This study has demonstrated that the acute inflammatory response is modified by exercise intensity in physically inactive adults with asthma, which also varied by phenotype of asthma. Moderate exercise was associated with reduction in sputum eosinophils exerting a beneficial effect. This anti-inflammatory effect also differed according to asthma phenotype. While moderate exercise was associated with a decrease in sputum eosinophilia in patients with eosinophilic asthma thereby modifying the acute eosinophilic inflammation in the airways, vigorous exercise was not. Patients should also be advised regular moderate exercise to control their asthma in addition to pharmacotherapy.

Reference

1. Scott HA, et al. Comparing the effect of acute moderate and vigorous exercise on inflammation in adults with asthma: a randomized controlled trial. Ann Am Thorac Soc. 2022 Jul 8. doi: 10.1513/AnnalsATS.202109-1053OC.